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ANNUAL PROGRESS REPORT 

August 25, 1962 to July 1, 1963 



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SUMMARY 




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DEPARTMENT OF THE INTERIOR 



UNITED STATES GEOLOGICAL SURVEY 






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ASTROGEOLOGIC STUDIES 
ANNUAL PROGRESS REPORT 
August 25, 1962 to 
July 1, 1963 

SUMMARY 
June 1964 



This preliminary report is distributed 
without editorial and technical review 
for conformity with official standards 
and nomenclature. It should not be 
quoted without permission. 



This report concerns work done on behalf of the 
National Aeronautics and Space Administration. 



DEPARTMENT OF THE INTERIOR 
UNITED STATES GEOLOGICAL SURVEY 






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CONTENTS 



SUMMARY 



Introduction 

Summary of Part A 

Part B 

Part C 

Part D 



Page 

5 

13 

18 

28 



INTRODUCTION 

This Annual Report is the fourth of a series describing the results 
of research conducted by the U.S. Geological Survey on behalf of the 
National Aeronautics and Space Administration. This report, which covers 
the period August 25, 1962 to July 1, 1963, is in four volumes corres- 
ponding to four main areas of research: Part A, Lunar and Planetary 
Investigations; Part B, Crater and Solid State Investigations; Part C, 
Cosmochemistry and Petrography; and Part D, Studies for Space Flight 
Program. An additional volume presents, in abstract form, summaries of 
the Papers in parts A, B, C, and D. 

The major long-range objectives of the astrogeologic studies pro- 
gram are to determine and map the stratigraphy and structure of the 
Moon's crust, to work out from these the sequence of events that led 
to the present condition of the Moon's surface, and to determine the 
processes by which these events took place. Work being carried out 
that leads toward these objectives includes a program of lunar geologic 
mapping; studies on the discrimination of geologic materials on the 
lunar surface by their photometric, polarimetric, and infrared proper- 
ties; field studies of structures of impact, explosive, and volcanic 
origin; laboratory studies on the behavior of rocks and minerals 
subjected to shock; study of the effect of stress history on the solid 
state properties of rocks; study of the chemical, petrographic and 
physical properties of materials of possible lunar origin and the 
development of techniques for their microanalysis and nondestructive 
analysis; and engineering studies in aid of the design of space flight 

experiments and the planning of space missions. 

ii 



Part A: Lunar and Planetary Investigations (with map supplement), 
contains the preliminary results of detailed geologic mapping on a 
1:1,000,000 scale of a major part of the equatorial belt of the Moon. 
Detailed geologic relations in certain areas and some regional geologic 
problems are discussed. 

Part B: Crater Investigations, includes a study of a naturally 
occurring analogue of a secondary crater ing event; a report on the 
progress of shock equation of state studies; reports on the high 
pressure polymorphs of silica, stishovite and coesite; and preliminary 
reports on field investigations conducted on meteorite craters of Campo 
del Gielo, Argentina, and the crypto-explosion structure of Flynn 
Creek, Tennessee. 

Part C: Cosmochemistry and Petrography, includes reports on the 
chemistry of tektites, their behavior during heating, the nature of the 
magnetic spherules visible in some tektites and evidence for their 
presence in submlcroscopic sizes in others. Reports on metallic iron 
and copper in stony meteorites are also included. 

Part D: Studies for Space Flight Program, includes reports on the 
determination of lunar slopes by photometric methods; a method for out- 
lining isotonal areas on the lunar surface; a derivation of the expected 
frequency of small craters on the lunar surface; and a report on the 
change of effective strength of target materials with crater size. 
Reports on a search for matter in the Earth-Moon libration regions, 
infrared studies, x-ray fluorescence of tektites, photogrammetry of small 
craters, and computer analysis of the pattern of varying albedo over 
the lunar terrain are also included. 

iii 



The following reports were published during the reporting period 
August 25, 1962 to June 30, 1963; 

Carr, M. H. , 1962, A shock wave technique for determination of densities 

at high temperatures using strain gauges (abs.): Am. Geophys. 

Union Trans., v. 43, no. 4, p. 455-456. 
Chao, E. C. T. , 1963, Geological occurrences of some southeast Asian 

and Austrailian Tektites (abs.): Am. Geophys. Union Trans., 

v. 44, no. 1, p. 93. 
Chao, E. C. T., and Littler, Janet, 1963, Additional evidence for the 

impact origin of the Ries basin, Bavaria, Germany (abs.), in 

Abstracts for 1962; Geol. Soc. America Spec. Paper 73, p. 127. 
Cuttitta, Frank, Chao, E. C. T., Annell, C, Carron, M. K. , and Fletcher, 

J. D. , 1963, The alkali content of Texas Tektites (abs.): Am. 

Geophys. Union Trans., v. 44, no. 1, p. 93. 
Eggleton, R. E., and Marshall, C. H. , 1962, Pre-Imbrian history of the 

lunar surface (abs.); Am. Geophys. Union Trans., v. 43, no. 4, 

p. 464. 
Fahey, J. J., 1963, Separation of coesite and stishovite (abs.), in 

Abstracts for 1962? Geol. Soc. America Spec. Paper 73, p. 149. 
Gault, D. E., Shoemaker, E. M. , and Moore, H. J., 1962, The flux and 

distribution of fragments ejected from the lunar surface by 

meteoroid impact (abs.); Am. Geophys. Union Trans., v. 43, 

no. 4, p. 465. 



Gault, D. E., Shoemaker, E. M. , and Moore, H. J., 1963, Spray ejected 

from the lunar surface by meteoroid impact: U. S. Natl. Aeronautics 
and Space Adm. Tech. Note D-1767, 39 p. 

Hackman, R. J., 1963, A lunar isotonal map (abs.): Photogramm. Eng., 
v. 29, no. 3, p. 477-478. 

Linnes, K. , Shoemaker, E. M. , and Sternberg, S., 1962, Television photo- 
graphy, in A review of space research- -Report of the summer study 
conducted under the auspices of the Space Science Board of the 
National Academy of Sciences at the State University of Iowa, Iowa 
City, Iowa, June 17-August 10, 1962: Natl. Acad. Sci.-Natl. Research 
Council Pub. 1079, p. 4-13 - 4-17. 

Marshall, C. H. , 1963, Geologic map and sections of the Letronne region 
of the Moon: U. S. Geol. Survey Map 1-385. 

Mason, A. C, and Hackman, R. J., 1962, Photogeologic study of the Moon, 
in Kopal, Zdenek, and Mikhailov, Z. K. , eds., The Moon- -Symposium 
no. 14 of the International Astronomical Union: London, Academic 
Press, p. 301-315. 

Mead, C. W. , Chao, E. C. T. , and Littler, Janet, 1963, Metallic spheroids 
from Meteor Crater, Arizona (abs.): Am. Geophys. Union Trans., 
v. 44, no. 1, p. 87. 

Milton, D. J., and DeCarli, P. S., 1963, Maskelynite--formation by 
explosive shock; Science, v. 140, no. 3567, p. 670-671. 

Moore, H. J., Gault, D. E., and MacCormack, R. W. , 1962, Fluid impact 
craters and hypervelocity--high velocity impact experiments in 
metals and rocks (abs.): Am. Geophys. Union Trans., v. 43, no. 4, 
p. 465. 



Morris, E. C. , and Stephens, H. G. , 1962, Photographic investigation of 
the Earth-Moon libration regions L, and L,. from Mt. Chacaltaya, 
Bolivia (abs.): Am. Geophys. Union Trans., v. 43, no. 4, p. 465. 

Roach, C. H. , Johnson, G. R., McGrath, J. G. , and Sterrett, T. S. , 1962, 
Thermoluminescence investigations at Meteor Crater, Arizona: Art. 
149 in U. S. Geol. Survey Prof. Paper 450-D, p. D98-D103. 

Shoemaker, E. M. , 1963, Application of photographic photometry to the 
geology of the lunar surface (abs.), in Proceedings of the Con- 
ference on lunar exploration, Blacksburg, Va., August 1962: 
Virginia Polytechnic Inst., Eng. Expt. Stat. ser. no. 152, pt. B, 
paper 10 , 1 p . 

Shoemaker, E. M. , 1963, Astrogeology , a new horizon (abs.), in Abstracts 
for 1962: Geol. Soc. America Spec. Paper 73, p. 241. 

Shoemaker, E. M. , 1963, Impact mechanics at Meteor Crater, Arizona, in 
Middlehurst, Barbara, and Kuiper, G. P., eds., The solar system, 
vol. IV- -The Moon, meteorites, and comets: Chicago, Univ. Chicago 
Press, p. 301-336. 

Shoemaker, E. M. , 1963, Manned spacef light--A challenge to geologists 
and geophysicists (abs.): A. Assoc. Petroleum Geologists Bull., 
v. 47, no. 2, p. 270. 

Shoemaker, E. M. , 1963, The Moon and planets, in Recent advances in 
space science: Am. Geophys. Union Trans. , v. 44, no. 1, 
p. 140-141. 



Shoemaker 5 E. M. , and Hackman, R. J., 1962, Stratigraphic basis for a 
lunar time scale, inKopal, Zdenek, and Mikhailov, Z. K. , eds., 
The Moon- -Symposium no. 14 of the International Astronomical Union: 
London, Academic Press, p. 289-300. 

Shoemaker, E. M. , Hackman, R. J., and Eggleton, R. E. , 1963, Interplane- 
tary correlation of geologic time, in Advances in the astronautical 
sciences, volume 8: New York, Plenum Press, p. 70-89. 

Steg, L. , and Shoemaker, E. M. , 1962, Libration point satellites, in A 
review of space research—Report of the summer study conducted under 
the auspices of the Space Science Board of the National Academy of 
Sciences at the State University of Iowa, Iowa City, Iowa, June 17- 
August 10, 1962; Natl. Acad. Sci.-Natl. Research Council Pub 1. 1079, 
p. 4-34-4-35. 

Thorpe, A. N. , Senftle, F. E., and Cuttitta, Frank, 1963, Magnetic and 
chemical investigation of iron in tektites: Nature, v. 197, no. 
4870, p. 836-840. 

Thorpe, A. N. , Senftle, F. E. , and Cuttitta, Frank, 1963, Magnetic and 
chemical studies of iron in tektites (abs.)s Am. Geophys. Union 
Trans., v. 44, no. 1, p. 92-93. 



Summary of Part A 

Geologic mapping of the Moon at a scale of 1:1,000,000 forms the base 
for the lunar investigations of the Geological Survey for the National 
Aeronautics and Space Administration. The geologic maps of the Kepler 
and Letronne quadrangles have been published in color. Preliminary 
geologic maps of the Copernicus quadrangle by E. M. Shoemaker and R. J. 
Hackman and Apennine Mountains quadrangle (now called Montes Apenninus) 
by R. Jo Hackman were transmitted to NASA previously. Maps accompanying 
this report include a recompilation of the Montes Apenninus quadrangle by 
R. J. Hackman based on excellent new photography taken at the 120" 
reflecting telescope at Lick Observatory, and preliminary geologic maps 
of the following quadrangles: Aristarchus by H. J. Moore, Timocharis 
by M. H. Carr, Riphaeus by R. E. Eggleton, Hevelius by J. F„ McCauley, 
and Mare Humorum by S. R. Titley. Mapping of the Ptolemaeus, Colombo, 
Theophilus, and Mare Vaporum quadrangles is in progress and will be 
completed in fiscal year 1964. Mapping also is in progress in the Mare 
Undarum, Langrenus , Pitatus, Grimaldi, Julius Caesar, Taruntius, and Mare 
Serenitatus quadrangles, and these will be completed in fiscal year 1965. 

Maps forwarded to date cover more than a million square miles or 
two million six hundred thousand square kilometers. By the end of fiscal 
year 1965, the maps of the lunar equatorial belt s amounting to more than 
three million square miles, should be completed. 




First phase target area 



Final map published Preliminary map, this report 



Second phase target area Preliminary map previously published Mapping in progress 

58 



m 



Modified preliminary map 



Copernicus 

ACIC number and name 
of region 



Figure 1. Index map of the Moon showing status of geologic mapping at a 
scale of 1:1,000,000. 



With the completion of mapping the first phase target area, the 
Lansberg Region—comprising the Copernicus, Kepler, Letronne and Riphaeus 
quadrangles --which is the nominal target area for the unmanned lunar 
probes of the Ranger and Surveyor projects, a re-evaluation was made of 
the fundamental assumptions underlying the discrimination of lunar strati- 
graphic units. The validity of the Copernican system, chiefly consisting 
of deposits of ray craters, Erathosthenian system of deposits of post- 
mare craters without rays, and the Imbrian system, including the Archimedian 
series, consisting of deposits of pre-mare craters, and the Apennian 
series, consisting of regional deposits related to the formation of the Imbriun 
basin, on which the Archimedian crater deposits rest, was affirmed. A major 
change introduced in the stratigraphic nomenclature in the central part 
of the Moon is the removal of the Procellarum mare material from a time 
stratigraphic unit - the Procellarian System - to a rock stratigraphic 
unit - the Procellarum Group - with two formations, mare material and 
dome material, that are included in the Archimedian Series of the 
Imbrian System, The change was made necessary by the realization that 
Archimedian type craters and mare material have a long and complex 
inter-related history. 

The typical lithostratigraphic breakdown of the rock units com- 
prising the deposits of major lunar craters are: crater rim material, 
floor material, slope material, central peak material, and ray material. 



These rock units have been given formational rank and in many places 
two or more lithofacies in each unit have been discriminated. 

The major part of the regional deposit of the Apennian Series, 
probably derived by ejection from the Imbrium Basin during its 
excavation, has been described in the Riphaeus quadrangle by R. E. 
Eggleton and named the Frau Mauro Formation. Another widespread 
unit which rests on the Frau Mauro Formation on the southern margin 
of the Imbrium Basin in the Montes Apenninus quadrangle has been 
designated the Apennine Bench Formation by R. J. Hackman. 

Geologic mapping in the Timocharis Quadrangle by M. H. Carr 
has led to the recognition of features suggesting that an erosional 
process has occurred on the lunar surface. Study of the numerous 
secondary craters related to the Copernicus and Eratosthenes primary 
craters has shown that the Copernicus secondary craters have distinct 
outlines, well-defined rim crests, and commonly have cuspate outlines, 
whereas the Eratosthenes secondaries of equivalent size have 
indistinct outlines that are not cuspate, have rounded rim crests, 
and are less deep. Because Eratosthenes is demonstrably older 
than Copernicus, the Eratosthenes secondaries are thought to be a 
degraded form of Copernicus secondaries. Similar differences are 
found between the Rima La Hire I and Rima La Hire II. Rima La 
Hire II has a distinct outline and steep walls. Rima La Hire I is 



indistinct, has rounded walls, and is very shallow. Hence Rima La Hire I 
is thought to be an older degraded rill. 

D. E. Wilhelms has encountered complex stratigraphy extending into 
the pre-Imbrian in his preliminary study of the Taruntius Quadrangle. 
Of unusual interest is the material of the Palus Somni which is smooth 
but has higher albedo than mare material of the Procellarum Group and 
is partly ringed with groups of small craters along its margins. In 
addition, in the Procellarum Group there appear to be at least two 
mappable types of mare material, one type being characterized by a 
distinct waviness of the mare surface. On the non-wavy mare material 
domes are probably more abundant than in any quadrangle studied so far. 
The majority of the domes have summit craters, but one has a small 

hill at its summit instead. Many craters on the maria seem to be aligned 
and there are also a number of rimless craters; Wilhelms suggests 
many of these craters are of volcanic origin. 

E. C. Morris has traced the distribution of the Apenninian Series 
in the western half of the Julius Caesar Quadrangle. He finds that the 
Apenninian Series has partly filled in the southeastern portion of the 
pre-Imbrian crater Julius Caesar more than the northwestern part, a 
relation that is interpreted to be the result of deposition of the 
Apenninian Series from low angle ballistic trajectories originating 
within the Imbrium Basin. Beneath the Apenninian Series there may also 



be a deposit of material derived from the region of Mare Serenitatis 
which partly fills the southern portion of Julius Caesar more than the 
northern. The combined result is a depositional floor sloping 
slightly west of north. 

Geological mapping of the Aristarchus Quadrangle by H. J. Moore 
has revealed a number of unusual features of probable volcanic origin. 
Broad circular or elliptical hills in the Harbinger Mountains, some 
with craters at their summits, have sinuous rilles on their flanks 
that extend on out onto adjacent mare surfaces. The material of the 
hills is similar in albedo to the mare material and has gradational 
contacts with the mare material. Moore has called it the Harbinger 
Mountains Formation which he interprets as consisting probably of 
volcanic flows or ash falls and flows. The Harbinger Mountains 
Formation may be of either Imbrian or Eratosthenian age. Other 
material of possible volcanic origin, including material under- 
lying Schroter's Valley and material comprising a group of hills 
near the head of the valley, named the Cobra Head Formation, and 
material associated with a number of smaller sinuous rilles, has 
been placed by Moore in the Copernican System. 

Mapping in the Hevelius Quadrangle by J. F. McCauley has led 
to investigation of the regional stratigraphic relations around 
Mare Orientale, a basin 320 kilometers in diameter, on the 



10 



western limb of the Moon. Two new rock stratigraphic units of Imbrian age 
have been recognized in the region around the Orientale Basin; 1) the 
Cordillera Group, comprising a regional deposit surrounding the basin 
and apparently similar in origin to the Apenninian Series, and 2) the 
Cruger Group, composed of crater materials superimposed on the Cordillera 
Group and overlain by the Procellarum Group. Both the Cordillera and 
Cruger Groups are in the Archimedian Series . 

Some of the oldest rock units were found by D. P. Elston during 
mapping on the Colombo Quadrangle. The oldest unit crops out in an 
arc of low hills of subdued relief peripheral to the northeast part 
of the Nectaris Basin and is informally named the Pyrenees Formation. 
It is interpreted to be the remnant of a regional blanket of material 
around the Nectaris Basin. The next younger unit comprises a distinct- 
ive group of crater deposits, characterized by the crater Gutenberg. 
The plan outline of this class of craters commonly is markedly poly- 
gonal, and crater floor material consists of jumbled blocks. Resting 
on the Gutenberg Crater deposits is a blanket of material that forms 
a plateau and highlands area in the northern part of the Colombo 
Quadrangle. This material, informally named the Censorinus N 
Formation, overlies, wholly or in part, several Gutenberg-type 
craters whose forms are still distinguishable through the blanket. 
The Censorinus Formation is interpreted to be part of a regional 



11 



blanket of material derived during an event that occurred to the north. 
The youngest unit of probable pre-Imbrian age in the quadrangle forms as 
a patchy veneer of smooth material on the Censorinus N Formation, and may 
be equivalent to other smooth materials of regional extent found peripheral 
to the Serenitatis and Imbrium Basins. 

New stratigraphic units of Imbrian to pre-Imbrian age were also 
recognized by S. R. Titley in his study of the Humorum Quadrangle. These 
are the Humorum Group , composed of a rim and a bench unit, and the 
Gassendi Group , representing the deposits of craters younger than Humorum 
Group but flooded by mare material of the Procellarum Group of Imbrian 
age. The units of the Humorum Group are peripheral to the Humorum Basin, 
a feature 300 km in diameter, the rim unit constituting part of a regional 
deposit apparently analogous to the Fra Mauro Formation and the Cordillera 
Group of McCauley. 



12 



Summary of Part B 

Brian J. Skinner and Joseph J. Fahey have investigated the inversion 
rate of Meteor Crater stishovite, a very dense form of SiCL in six-fold 
coordination, which inverts to silica glass in four-fold coordination. 
The inversion rate, determined at ten temperatures between 300° and 800 °C 
and extrapolated to the time for total inversion of stishovite to silica 
glass, indicate the virtual impossibility that stishovite can be formed 
and preserved at the surface of the earth by any mechanism other than 
meteorite impact. 

Coesite and stishovite, the high pressure polymorphs of silica., were 
recovered by Joseph J. Fahey from the shocked Coconino Sandstone at 
Meteor Crater by repeated treatments using hydrofluoric acid, but much 
less readily than is quartz, and can be obtained by repeatedly heating 
the host material with a 5 percent solution of hydrofluoric acid at 25°C. 
Colloidal and suspensoidal particles of coesite can then be separated 
from the residual quartz by repeated shaking and decantation in water. 

Further, detailed geologic mapping by E. M. Shoemaker and R. E, 
Eggleton on the east flank of the nearly circular Sierra Madera disturbance 
in West Texas, identified three previously unrecognized units: The 
Tessey Formation of Permian age, a thin section probably of the 
Bissett Formation of Triassic age, and a thin unit of probably Triassic 
claystone. The presence of these units shows there is no significant 



13 



angular unconformity between the rocks of Permain and Cretaceous age. To 
date, the detailed mapping has been confined to a zone of thrust faults 
and related folds that surround a central lens of megabreccia. The 
thrusts dip toward the center and the upper plates are displaced outward. 
Within each thrust plate the beds are buckled and locally cut by subordinate 
thrust faults and be steeply-dipping normal reverse and tear faults. Horse 
blocks of the basement Sandstone of Cretaceous age occur along the 
thrusts and tear faults. Eastward from the center of the structure, 
displacement on the thrust faults decreases, thrusts die out in asymmetrical 
anticlines with axial planes dipping back toward the center, and the 
intensity of buckling decreases. 

The additional data are compatible with the concept that the 
structure resulted from meteoritic impact. 

An expedition consisting of representatives from Lamont Geological 
Institute, Direcion de Geologia y Miner ia, Argentina, Mellon Institute, 
and Carnegie Institute of Technology, and Daniel J. Milton of the 
Geological Survey made the first detailed examination of the Campo del 
Cielo, Argentina meteorite and crater field. The expedition confirmed 
the impact origin of several craters, located and mapped seven craters, 
and acquired a newly found iron meteorite of about three tons for the 
U. S. National Museum. In addition, the number of small iron meteorites 
collected from this field was increased from a handful to more than 
400 establishing Campo del Cielo as probably the largest known meteorite 



14 



strewn field. Excavation of the best preserved crater revealed charcoal 

that may represent wood buried beneath loose throwout and burned in a 

14 
fire caused by the meteorite fall. Carbon age of charcoal was deter- 
mined by Wallace Broecker of Lamont Observatory as 5,800, +200 years. 

A group of fresh, low velocity impact craters formed by a 950-foot 
rock fall of Toroweap Sandstone into the dry sand bed of the Little 
Colorado River, about 15 miles west of Cameron, Arizona was studied by 
D. P„ Elston and D. J. Milton. One crater, having a diameter 5-7 feet 
and a depth of 2 feet, was formed by impact of a block of sandstone 
weighing about 175 pounds into a nearly level, slightly coherent sand 
bank. An apron of ejecta was deposited asymmetrically in a direction 
dominently away from the source of the rock fall and consisted of (1) 
a continuous blbcky sand ejecta blanket extending from the crater lip 
to as much as four feet from the crater, and (2) a discontinuous sand 
ejecta blanket, in part ray-like, that extended to about 14 feet from 
the crater. The blocky blanket formed a distinct "hummocky" crater 
rim deposit. Geologic relations indicate that the material of the 
discontinuous blanket was deposited upon and beyond the crater rim 
deposit and was derived from the deepest part of the crater. Fragments 
of the impacting projectile were deposited in elongate trains trace- 
able up the crater wall, across the blocky ejecta apron, and into the 
ray-like areas, forming the roughest material in the discontinuous 



15 



blanket. Craters such as this provide a good approximation of secondary 
impact craters, which are thought to be important features contributing 
to lunar topography. 

Geologic mapping of the Flynn Creek, Tennessee, cryptoexplosion 
structure has been nearly completed by D. J. Roddy. The field studies 
have delimited, in an otherwise undeformed area, a circular deformed 
rim of Ordovician rocks, about 2.2 miles in diameter, enclosing an 
intensely brecciated rock consisting of rock fragments of Middle and 
Upper Ordovician age. The upper surface of the breccia is in the form 
of a crater, 300 feet deep, which contains a centrally raised structure 
of intensely disturbed rocks of Middle Ordovician age. The structure 
formed sometime in the interval that includes Late Ordovician to 
early Late Devonian time. A. thin marine deposit of bedded breccia 
and cross bedded dolomite, possible basal Chattanooga, and an anomalously 
thick section of Chattanooga Shale of early Late Devonian age were 
deposited in the crater-form structure. The character of the breccia-, 
the presence of shatter cones, the gross structural form, and the 
apparent lack of gravity and magnetic anomalies in detailed geophysical 
surveys, are compatible with a meteoritic impact origin. 

Work has continued by M. H. Carr on the development of a rapid, 
inexpensive technique for explosively shock loading materials to permit 
the study of their behavior under varying pressure conditions . The most 



16 



fruitful use of this technique is in shocking rock materials to known 
peak pressures so that the effects of known shocks on a variety of 
materials can be studied. This experimental technique can be used to 
obtain the Hugoniot or shock equation of state of a rock material and 
consists of passing an explosively generated shock wave through an- 
aluminum rod and then through the specimen. The time of passage of the 
shock wave past strain gauges on the aluminum and specimen are measured 
and the shock speeds are determined. From the two shock speeds, the 
shock equation of state can be determined by an impedance match 
solution, provided the shock wave in the specimen is a single step 
function. The technique, applied to copper, gave results that are 
in good agreement with the previously determined Hugoniot for copper. 
The results for Yule Marble indicate that a multiple wave structure 
is generated; thus an impedance match solution is invalid and no 
Hugoniot curve can be constructed. Results on Vacaville Basalt show 
that the measured speed of the shock wave is not pressure dependent 
and was essentially constant at 5.76, +. 23km/ sec over the pressure 
range studied. These results are similar to that found for gabbro by 
other workers, and may result from measurement of an elastic precursor 
at pressures less than 200 kb. 



17 



Summary of Part C 

New analyses for major and minor elements and physical-property 
determinations on 6 australites and 6 javanites have been made by F. 
Cuttitta, E. C. T. Chao, M. K. Carron, J. Littler, J. D. Fletcher, and 
C. Annell. New minor element analyses have also been performed on 6 
indochinites, 1 additional javanite, 15 philippinites , and 2 thailandites , 
The new data indicate that Australasian tektites comprise at least 
two distinct chemical populations which are characterized by differences 
in 1) indices of refraction and specific gravities, 2) MgO/CaO ratios, 
3) Cr, Ni, and Co contents, and 4) Cr/Ni ratios. The analyzed 
australites are similar to philippinites in that both kinds of 
tektites have MgO/CaO less than one and have low Cr, Co, and Ni 
contents. Indochinites and javanites are characterized by MgO/CaO 
values greater than one and Cr, Co, and Ni contents that are higher, 
in general, than in australites and philippinites. Physical and 
chemical data, such as these, point toward a better understanding 
of the extent of intermixing of tektites within each of the various 
regions comprising the Australasian strewnfield, and thereby, a 
means of reconstructing fall patterns. 

E. C. T. Chao, E. J. Dwornik, and J. Littler have reported new 
mineralogic, petrographic, and chemical data on metallic spherules 



18 



present in philippinites from the Ortigas site of Mandaluyong near 
Manila, Philippines, and in indochinites from Dalat, South Viet Nam. 
Most of the spherules contain kamacite, schreibersite, and troilite. 
Schreibersite is interstitial to the round or elongate, fine-grained 
kamacite, or forms blebs in a matrix of this kamacite. Where 
abundant, schreibersite forms a network throughout the entire 
spherule. Troilite generally comprises small round inclusions in 
the schreibersite. The amount of schreibersite in the spherules ranges 
from less than 5 to about 35 modal percent and the troilite constitutes 
as much as 5 modal percent. 

The composition of the phases present in the metallic spherules 
was determined by use of the electron probe. The kamacite from 
metallic spherules in 9 philippinites contains from 1.6 to 4.5 percent 
Ni. The average Ni contents of kamacite in each of 3 analyzed spherules 
from indochinites are 4.7, 10.0, and 12.9 percent. The average Ni 
contents in each of 4 schreibersite grains in a single indochinite 
spherule ranges from 12.1 to 15.8 percent. 

The spherules in the tektites are very similar to the meteoritic 
spheroids from Meteor Crater, Arizona, in texture and mineral assemb- 
lage. It is concluded that the spherules in the tektites were formed 
as molten droplets from an impacting meteoritic body which was instrumental 
in producing the tektite glass. 



19 



The magnetic properties of metallic spherules in tektites from 
Isabela, Philippine Islands, have been investigated by F. E. Senftle, 
A. N. Thorpe, and R. R. Lewis. Five metallic spherules from a single 
tektite were studied. They ranged from 0.02 to 0.04 cm in diameter and 
from 0.07 to 0.28 mg in mass. An electron probe analysis of one spherule 
confirmed the report of Chao and others (1962) that silicon, if present, 
is less than a few tenths of a percent. 

Magnetic susceptibility measurements on the spherules were made by 
the Faraday method using a quartz helical spring balance. Measurements 
were taken at temperatures ranging from 303° to 77 C K. The susceptibility 
was found to be independent of temperature and approximately the same 
in all spherules for given field strengths up t o 6000 oe. Measurements 
of magnetic susceptibility as a function of field strength at 298° and 
77° K showed that saturation occurs at relatively high field strengths 
compared to the saturation of pure iron. The specific magnetization of 
two of the spherules is about 1.85 Bohr magnetons per atom in fields in 
excess of 6000 oe. The permeability of the spherules is close to 1.38. 

The large field - and temperature - independent susceptibility 
(0.03 emu/g) is not to be expected for an iron alloy of the composition 
of the spherules (about 3 percent Ni and 97 percent Fe). Some Ni and 
low-Si iron alloys lack magnetic saturation except at high fields as do 
the spherules, however, such alloys have very large permeabilities in 



20 



contrast to the low permeability of the spherules. Also, the specific 
magnetization of the spherules is much higher than would be expected 
for a low-Ni iron alloy, but can be accounted for by the presence of 
Fe-Ni phosphides. These considerations indicate that the apparently 
abnormal magnetic properties of the spherules cannot be a direct result 
of their chemical composition. 

The field-independent susceptibility of the spherules, except in 
very high fields, indicates the absence of a magnetizing field within 
the spherule. Considerations of the resultant field inside a spherule 
as a function of the applied field, the shape of the spherule, and the 
saturation magnetization shows that the field - and temperature - 
independent susceptibility is a direct result of the shape of the 
spherules. 

The saturation of the spherules at relatively high field strengths 
indicates that the use of the equation of Owen (1912) and Honda (1910) 
to detect gross ferromagnetic impurities in tektites is valid only if 
there are no spherules present. Thus, the presence of spherules less than 
lji in diameter cannot be detected by this method or by microscopic 
examination. 

Senftle, Thorpe, and Lewis have also found that measurements 
of magnetic susceptibility as a function of temperature is a possible 
technique for the detection of submicroscopic, metallic spherules. 



21 



The presence of a temperature -independent component of the susceptibility 
appears to indicate the presence of submicroscopic spherules. If the 
presence of spherules is established for tektites in general, it will give 
additional evidence of a meteoritic origin for tektites when combined with 
the known existence of relatively high phosphorus and nickel contents of 
the metallic spherules. 

Additional magnetic susceptibility measurements by Thorpe and Senftle 
on 18 tektites from various strewn fields have shown a relatively large 
temperature -independent component of the magnetic susceptibility in all 
cases. The data indicate that this component is the result of submicro- 
scopic iron spherules in the tektites. An investigation of the color 
of tektites in terms of the magnetic measurements and of the optical 
absorption spectra suggests that the basic color of all tektites is 
green or greenish-blue. The brown to black coloration in some tektites 
appears to be due to finely dispersed Fe 0. and/or many submicroscopic, 
metallic spherules. 

The vapor pressure and vapor fractionation of Philippine tektite 
melts of approximately 70 percent SiCL have been studied by L. S. Walter 
and M. k. Carron. The total vapor pressure at temperatures ranging from 
1500° to 2100°C pressure is 190 +40 mm Hg at 1500°C, 450 +50 mm at 1800°C, 
and 850 +70 mm at 2100°C. Determinations were made by visually observing 
the temperature at which bubbles began to form at a constant low ambient 
pressure. By varying the ambient pressure, a boiling point curve was 



22 



constructed. This curve differs from the equilibrium vapor pressure 
curve due to surface tension effects. This difference was evaluated 
by determining the equilibrium bubble size in the melt and calculating 
the pressure due to surface tension, assuming the latter to be 380 
dynes /cm. 

The relative volatility from tektite melts of the oxides of Na, 
K. Fe, Al, and Si has been determined as a function of temperature, 
total pressure and oxygen fugacity. The volatility of Si0„ is decreased 
and that of Na„0 and K is increased in an oxygen-poor environment. 
Preliminary results indicate that volatilization at 2100°C under 

atmospheric pressure caused little or no change in the Na~0 or K„0 

3 2 
percentage. The ratio Fe /Fe of the tektite is increased in ambient 

-4 -7 4 

air at a pressure of 9 X 10 mm Hg (=10 * atm 0_ , partial pressure) 

at 2000° C. This suggests that tektites were formed either at lower 

oxygen pressures or that they are a product of incomplete oxidization 

of parent material with a still lower ferric-ferrous ratio. 



23 



C. S. Annell has investigated the analysis of solutions by emission 
spectroscopy as a technique for the quantitative determination of the 
major constituents of tektites and meteoritic materials . Use of rotating 
disc apparatus in conjunction with high voltage spark, excitation produces 
the characteristic spectra of many elements present in these materials. 
The spectral intensities can be measured and quantitatively related to 
known standards. Studies of experimental factors show that excellent 
working curves covering the elemental ranges exhibited by known tektites 
are obtained for aluminum, iron, magnesium, calcium, and titanium. 
Methods for detecting or determining other elements present in tektites 
are being studied. 

A spectrographic method for the determination of Cs , Rb, and Li 
in less than 10 ppm concentrations in tektites has also been developed 
by Annell. A 1 ppm analytical limit for Cs was obtained using a. 3 -meter 
concave grating spectrograph. The method was primarily designed to 
determine the Cs content of tektites, with adaptation to Rb and Li 
determinations . The precision of the method was checked by duplicate 
determinations of Cs , Rb, and Li in bediasites from Texas and tektites 
from Southeast Asia and Indonesia. 

M. K. Carron has developed modifications of Wilson's (1960) method 
for the determination of ferrous iron in milligram amounts of silicates. 
The modifications provide a means for high-precision determinations of 



24 



ferrous iron in tektites using ordinary semi -micro laboratory equipment. 
The method presented here employs more dilute solutions of vanadium 
(V) (0.0139N) than proposed by Wilson. The excess vanadium (V) remaining 
in solution, after oxidation of the ferrous iron of the sample, is 
titrated with a 0.0139N ferrous ammonium sulfate solution, using a 
semi -micro burette graduated to 0.02 ml. The results obtained by the 
proposed method show excellent agreement with those obtained 
spectrophotometr ically . 

Methods using semi -micro X-ray fluorescence analysis of 50 mg 
samples of tektites have been developed by H. J. Rose, Jr., F. 
Cuttitta, M. K. Carron, and R. Brown. Determinations of Si0„, 
A1 ? , total iron, K„0, CaO, TiO. , and MnO are in agreement with 

those obtained by conventional chemical techniques . 

i 
Metallic iron, occurring as a minor constituent in the basaltic 

achondrites , has been investigated by M. B. Duke. New electron probe 

analyses and petrographic data have been obtained from kamacite in 

six eucrites and one howardite. The low nickel content of kamacite 

in eucrites has been verified. Emission spectrographic analyses for 

nickel in pyroxene from several types of stony meteorites (Duke, 1963) 

and new electron probe analyses for nickel in the coexisting kamacite 

give a distribution factor that is in fair agreement with experimental 

determinations at atmospheric pressure and magmatic temperatures. The 



25 



low nickel content of the metal and the generally low total nickel content 
of the basaltic achondrites is interpreted as due to fractionation between 
metal and silicate phases during magmatic differentiation of the basaltic 
achondrites. The nickel distribution supports Other mineralogical and 
textural evidence that these rocks formed at relatively low pressures. 

Metallic copper from the Norton County achondrite has also been 
investigated by Duke in collaboration with Robin Brett, of the Carnegie 
Geophysical Laboratory. Electron microprobe analyses of the copper 
indicate an iron content of 4.2 weight percent (Keil and Fredriksson, 
1963). 

However, phase equilibria relations from the system Cu-Fe-S 
(R. A. Yund, pers . coram.) suggest that the copper was formed below 
475 +25°C, the temperature at which iron solubility in copper is 
negligible. Therefore, new electron probe microanalyses wave made of 
copper grains (5u to 20;i) from the chondrites Miller, Penokee, and 
Bath. Iron contents ranging from 1.1 to 4.5 weight percent were obtained. 
Determinations varied within single copper grains, suggesting that analy- 
tical uncertainties were involved. 

In order to assess the magnitude of CuKy induced FeKjfradiation 
arising from outside the analyzed copper grains, four iron fragments 
were polished and given coats of metallic copper ranging from 0.8 to 
3.5ji in thickness. These were analyzed with an ARL and the U. S. G. S* 



26 



microprobe. The intensity of induced FeKo( radiation apparently decreases 
exponentially with the thickness of the copper layer, but is equivalent 
to 3 weight percent or more for iron covered by 3.5;i of copper. The 
lower the excitation potential or the lower the X-ray take-off angle, 
the smaller is the fluorescence effect. 

On the basis of the phase equilibria data and the experiments with 
copper-coated iron, it is suspected that the analyzed values of iron in 
copper are unreasonably high due to fluorescence effects. It is necessary, 
therefore, to analyze large grains or separate the copper from the matrix 
in order to determine the true iron content . 



27 



Summary of Part D 

A photometric technique for measurement of lunar slopes has been 
developed by D. E. Wilhelms. The technique is based on the assumption 
that for slopes on lunar surface material of uniform albedo, the apparent 
brightness depends only on the angle of incidence of the sun's rays; 
therefore, slopes of equal brightness at two separate points differ by the 
difference of angle of incidence between the points. The angle of inci- 
dence can be determined at all points on any photograph whose time of 
exposure is known; if the slope at one point is known, the other can be 
easily calculated. 

Horizontal areas are used as the known slopes. Brightness of 
segments of .75 to 1.5 km square of the lunar surface are determined 
by a microphotometer, along traverses perpendicular to the terminator. 
The record is in the form of both an inked line on a chart and a punched 
paper tape. With the chart, the curve which passes through horizontal 
segments can be drawn for each albedo unit (normal albedo must be 
mapped in advance by other techniques, such as that described below, 
using full-moon photography). The curve then serves as a comparison 
curve against which brightness of non-horizontal slopes can be matched. 
Angular distances in lunar longitude from the terminator, which closely 
correspond to the inclination of the sun's rays, are scaled off on the 
chart. By measuring the difference in longitude between the segment of 



28 



unknown slope and the point of equal brightness on the comparison curve, 
the calculation of the slope is readily made. 

By means of the punched tape, the calculations can be performed by 
computer. Since the report period, J. F. McCauley has successfully 
automated the technique, including automatic derivation of the comparison 
curves, and applied it to a large portion of the lunar equatorial belt, 
using existing telescopic photographs. In the future when photographs 
obtained from spacecraft become available, it should be possible to 
measure slopes of smaller segments than .75 km by refinement of the tech- 
nique. Terrain maps obtained by this method are of great importance in 
planning unmanned and manned spacecraft landings. 

Details of construction of an isotonal map of the Lansberg region 
are given by R. J. Hackman. Areas of equal density, determined by micro- 
photometer, were outlined on a full-moon photograph. A high-contrast 
positive print (transparency) was used which enhanced tone differences 
in dark areas (maria) , while suppressing those of light areas (terrae 
and rays). 

While the densitometer was measuring density along traverses across 
the transparency, the lines of traverse were being automatically plotted 
on a Cronopac print of the same area on the same scale. The densitometer 
curves were recorded simultaneously on graph paper. These curves were 
compared periodically with a curve run over a standard density wedge, and 



29 



the standard wedge steps scaled off on them; the curves were thereby 
divided into density units. The segments along the traverse corresponding 
to each of the density units were plotted on a 1:2,000,000 enlargement of 
the photograph. With these segments (along with 600 spot measurements) 
as control, and tonal patterns as visual aids, isotonal lines connecting 
points of equal density were drawn on the photograph. For the final por- 
trayal of the map, the isotonal lines were transferred to ACIC Mercator 
projection lunar topographic charts by means of a Sketchmaster . 

The tone values obtained are relative. They are compared with absolute 
normal albedo measurements made by other investigators by other methods. 

Similar tone values are often a clue to correlation of lunar geologic 
units separated from one another. An isotonal map such as the one compiled 
correlates tones with greater precision than the unaided eye because the 
eye is influenced by surrounding tones. Also, small tonal variations that 
would escape the eye are detected by the densitometer. Isotonal maps are 
a prerequisite to the construction by photometric methods of lunar terrain 
maps, as described above, because effects of albedo must be separated 
from ef fects )of variation in slope. 

Kenneth Watson gives a historical summary of lunar infrared emission 
studies, and against this background, describes the investigations to be 
carried out in this field by the Branch of Astrogeology . Information from 
both temporal and spectral distribution of infrared emission will be 



30 



utilized in interpretation and correlation of lunar geologic units. Both 
broad-band and narrow-band emission within the two major atmospheric win- 
dows of 8-14u and 18-24u will be examined. The broad-band studies will 
provide information on the distribution of thermal properties at and near 
the surface, while narrow-band studies will primarily provide information 
on the grain-size distribution of the lunar material, and possibly, in the 
case of bright-ray craters, a limited amount of compositional analysis. 
An important line of research will be the computation of models p supported 
by experiment and observation, to explain the infrared emission. At 
present, studies are being made on the use of models of the lunar photometric 
function to derive the variation of absorbed solar energy as a function 
of the inclination of the sun's rays. 

Calculations of the density of small (telescopically unobservable) 
craters on the lunar surface are given by H. J. Moore. The results differ 
significantly from extrapolations of frequencies of telescopically observable 
craters 1 kilometer in diameter or larger. By combining data on hypervelo- 
city impact cratering and data on the distribution of interplanetary dust, 
micrometeoroids , meteoroids, and asteroids, it is calculated that a 
billion-year-old surface composed of rock or sand would be completely 
covered with primary craters of all sizes up to 1 meter across in 
various stages of destruction. If craters 100 meters in diameter are destroyed 
by erosion and infilling in a billion years, about 10 percent of such a 



31 



surface could be covered by well preserved craters between 1 and 10 meters 
in diameter, 10 percent by well preserved craters between .1 and 1 meter, 
and 10 percent by well preserved craters between .01 and .1 meter. The 
remaining surface area would be covered by primary craters .01 to 10 
meters in diameter that are more than three-tenths destroyed, by rare 
larger craters, and by secondary impact craters. Secondary craters should 
be about one-tenth as abundant as primary impact craters of the same size 
except around large young primary craters, where secondary craters would 
be abundant . 

Higher rates of crater destruction, as might result from flow of 
material or burial by volcanic products, would substantially alter these 
predictions. A smaller crater density is expected on surfaces younger 
than one billion years. 

H. J. Moore, D. E. Gault, and E. D. Heitowit show experimentally 
that there is a decrease in effective target strength in basalt with 
increasing size of hypervelocity impact craters. The results are 
consistent with defect theory, which predicts a decrease in strength with 
increasing size of specimens containing defects. The experiments refute 
predictions that the amount of mass ejected for each unit of projectile energy 
(corrected for the projectile-target density ratio) should be constant. 

Photogrammetric techniques for the construction of topographic and 



32 



structural maps of small experimental impact craters are described by 
R. V. Lugn. Two overlapping photographs of the crater are taken normal 
to the surface of the target block. Vertical and horizontal scales are 
determined by comparing measurements of the crater with corresponding 
measurements made on the stereo model. Then, topographic and structural 
maps are prepared using standard procedures. These methods are essenti- 
ally the same as those used in conventional aerial mapping. 

Continued investigations of the Earth-Moon libration regions L. 
and L,., at Mt. Chacaltaya, Bolivia, are reported on by E. C. Morris, J. Ring, 
and H. G. Stephens. The libration points, lying in the orbital path of 
the Moon 60 degrees ahead of and behind it, are points of equilibrium 
where centrifugal forces balance gravitational forces. It was hoped to 
observe clouds of particles ("Kordylewski's clouds") which may be trapped 
at these points. During the summer and fall 1963, 17 photographic plates 
of L, and 28 plates of L were taken with a 12-inch focal length aerial 
camera. Visual examination and microphotometer measurements of the plates 
failed to show any brightening in the region of the libration points. 
Further statistical analysis of the plates is planned. In addition, photo- 
electric scans were made with a 6-inch-diameter Maksutov-Cassegrain tele- 
scope. Data from the scans are being reduced; preliminary reductions show 
no indication of the presence of a cloud. With further reductions , it 
is hoped to place an upper limit on the possible cloud brightness. The 



33 



particle density corresponding to this brightness will be calculated. 

X-ray fluorescence analyses of tektites, using 50 milligram samples, 
have been performed by H. J. Rose, Jr., F. Cuttitta, M. K. Carron, and 
R. Brown. X-ray fluorescence spectroscopy had been applied previously in 
the analysis of materials of geologic interest, but larger samples had 
hitherto been required. Six Java tektites, representative of the range 
of indices of refraction and specific gravities from a large collection, 
were analyzed both by X-ray fluorescence and chemical methods, and the 
results compared. The analyses, including those of the light elements, 
are closely similar. 

A. T. Miesch and C. W. Davis have written computer programs designed 
to analyze microphotometric data from lunar photographs. Standard statis- 
tical parameters such as the mean, standard deviation, skewness, kurtosis 
and frequency distribution are computed from the data for a particular 
geologic unit. Also polynomial regression curves are fitted to the data 
so that regional variations in reflectivity may be distinguished from local 
variations. Serial correlation surfaces are computed for data from the same 
geologic unit. These surfaces provide a means of measuring the coarseness 
in texture of the albedo patterns and also provide a useful tool for correla- 
tion of rock units. The program as a whole enables the reflectivity varia- 
tion of different geologic units to be described in quantitative terms. 
Correlation between rock units is thereby facilitated and a better under- 
standing of the nature of the reflectivity variations is achieved. 



34